Fuel filter

ABSTRACT

A fuel filter for engines of automobiles comprising a closed casing, a filter element in the casing, a fuel inlet pipe extending through the wall of the casing and opening in the casing for introducing the fuel to be filtered into the space around the element, and a fuel outlet pipe extending through the wall of the casing and opening within the filter element at a level lower than that of the opening of the fuel inlet, the said fuel outlet pipe being formed with a small by-pass opening in the upper portion of the wall of the fuel outlet pipe extending in the filter element, so that the water content of the fuel when accumulated and frozen in a cold season will not clog the fuel inlet of the filter, and that sufficient fuel supply for a cold start of the engine will be ensured through the said by-pass opening.

United States Patent Saito et al.

[ 1 June 27, 1972 1 FUEL FILTER {72] Inventors: Nobuo Saito,Saitama-ken; Kyojl Namlkl,

Urawa, both of Japan [73] Assignee: Kabushlkl Kalsha TsuchiyaSelsakusho,

Toyko, Japan [22] Filed: Aug. 24, 1970 [211 App]. No.: 66,309

[30] Foreign Application Priority Data May 19, I970 Japan ..45/42090[52) U.S.Cl ..210/438 [51] Int.Cl 1 ..B01d 29/00 [58] Field olSearchm.,,210/307,435-441, 210/452, 457

[56] References Cited UNITED STATES PATENTS 3,465,883 9/1969 Jumper 1210/307 3,237,770 3/1966 Humbert, Jr. 210/438 X 73,105 1/1868 Lighthall..210/439 Primary Examiner-Reuben Friedman Assistant ExaminerR. W. BurksAttorney-Karl W. Flocks [57] ABSTRACT A fuel filter for engines ofautomobiles comprising a closed casing, a filter element in the casing,a fuel inlet pipe extending through the wall of the casing and openingin the casing for introducing the fuel to be filtered into the spacearound the element, and a fuel outlet pipe extending through the wall ofthe casing and opening within the filter element at a level lower thanthat of the opening of the fuel inlet, the said fuel outlet pipe beingformed with a small by-pass opening in the upper portion of the wall ofthe fuel outlet pipe extending in the filter element, so that the watercontent of the fuel when accumulated and frozen in a cold season willnot clog the fuel inlet of the filter, and that sufficient fuel supplyfor a cold start ofthe engine will be ensured through the said by-passopening.

4 Claims, 4 Drawing Figures FUEL FILTER BACKGROUND OF THE INVENTION Thisinvention relates to a fuel filter for engines of automobiles.

A fuel filter of known type has a fuel inlet in the lower portion of thecasing, with a consequence that the water content of the fuel flown inis collected on the bottom of the casing. Because the accumulated waterif admitted into the engine can have an adverse effect, it must beremoved from the filter casing at suitable intervals. In reality,however, it is not unusual that the dewatering is carelessly neglected.Then, if the engine is stopped with the filter casing containing toomuch water and allowed to stand in a cold season, the water may freezeand clog the fuel inlet of the filter and make the starting of theengine totally impossible.

An attempt at precluding this possibility has been to provide the fuelinlet in the upper portion of the casing. Still, the water, if allowedto collect until the water level exceeds the lower end closure plate ofthe filter element, will permeate into the filter element and eventuallythe water levels in and out of the element will become equal, thusmaking the removal of water difficult. Negligence of dewatering for aprolonged period of time will raise the water level to a point near thefuel inlet in the upper portion of the casing and, if the fuel filter inthat state is left unused in a cold season, the water will freeze andthe resulting ice will, in the long run, choke up the fuel inlet.

SUMMARY OF THE INVENTION The present invention is directed toimprovements over the known filters through elimination of the foregoingdisadvantages inherent to the latter.

More specifically, the present invention has for its object to provide afuel filter of the type which filters fuel through a filter element of afibrous material such as paper which is accommodated in a casing, sodesigned that the water content of the fuel even if excessively gatheredin the filter casing and inside the element and frozen therein in a coldseason will not clog the fuel inlet and that the fuel passage will besecured at the start of the engine by a by-pass opening formed in thefuel outlet pipe.

The above object is realized by a construction such that a fuel outletpipe is provided as is suspending in the element, with the lower endextending below the fuel inlet so that the water level will not ascendthereabove, thus avoiding the possibility of the inlet being choked upfollowing the closure of the outlet pipe with frozen water, and a smallby-pass opening is formed in a relatively upper portion of the outletpipe to ensure at least a minimum of fuel supply through the by-passopening of the said outlet to permit starting of the engine which isotherwise infeasible with an ordinary fuel filter.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a vertically sectional viewof an embodiment of the present invention;

FIG. 2 is a horizontally sectional view of the embodiment;

FIG. 3 is a plan view of the embodiment; and

FIG. 4 is a vertically sectional view of another embodiment of theinvention.

DETAILED DESCRIPTION OF THE INVENTION Referring to the accompanyingdrawing showing preferred embodiments of the present invention, a filtercasing cover 1 is made of a synthetic resin material, e.g., nylon, andhas a fuel feed pipe 2 in communication with a fuel outlet pipe 8 whichis secured to the center of the casing cover 1 as if hanging downtherefrom. A casing 3 is made of the same material as the cover has afuel inlet pipe 4 integrally formed along a vertical wall of the casing.The opening 10 at the upper end of the inlet pipe 4 is open in the upperspace inside the casing. A filter element 5 of an ordinary constructionadapted to be placed in the casing is fabricated of a filter paperfolded and pleated in the usual manner, and is liquid-tightly sealed atthe upper and lower ends with end closure plates 6 and 7, respectively.The upper end closure plate 6 is bonded to the under-side of the cover 1so as to surround the outlet pipe 8. The opening at the lower end of theoutlet pipe 8 is open at a point below the upper end opening 10 of theinlet pipe 4, and a by-pass opening 9 is formed near the upper end ofthe outlet pipe 8v As seen in FIGS. 1 and 4, the by-pass opening 9 issmall as compared with the end opening of the outlet pipe 8. It isobvious that the presence of the small by-pass opening 9 will not affectthe sucking operation of the outlet pipe 8 through the lower end openingthereof. Fuel flows in through the inlet pipe 4 and, from the upper endopening 10 of the inlet pipe, enters the space defined between theelement 5 and the casing 3, and is filtered as it passes through theelement. The filtered fuel enters the opening at the bottom of theoutlet pipe 8 and flows through the outlet pipe 8 and the feed pipe 2toward the engme.

While the fuel is flowing, it leaves its water content behind in thecasing as already stated. Water is thus slowly collected in and out ofthe element with gradual rises of the levels. If the removal of thiswater is neglected, the water collected undemeath the element bottom 13will increase until the water level reaches the opening at the lower endof the outlet pipe 8. This shuts off the flow of fuel and the fuel,therefore, tends to pass through only the by-pass opening 9 to flow intothe feed pipe 2. However, because the cross sectional area of the bypassopening 9 is by far the smaller than that of the upper end opening 10 ofthe inlet pipe 4, water and fuel virtually in the form ofa mixture flowup and over the outlet pipe 8 from the lower end thereof. As a result,the mixture of fuel and water flows out into the engine from the lowerend opening of the outlet pipe, the water being in an amount equal tothe amount that is supplied from the inlet together with the fuel. Forthis reason, the water inside the element will not collect to a levelabove the opening at the lower end of the outlet pipe, and there is nodanger of clogging of the upper end opening l0 of the inlet pipe whichis located above the lower end opening of the outlet pipe.

However, if the water collected in the element is frozen by a lowambient temperature, the opening at the lower end of the outlet pipe iscompletely closed. Nevertheless, according to this invention, theopening of the inlet pipe 4 is never clogged by the water frozen andexpanded in volume inside the casing 3, thanks to the opening of theinlet pipe 4 which is located below the opening at the lower end of theoutlet pipe 8.

When the engine is started in this state, the fuel manages to flowthrough the by-pass opening 9 via a part of the filter ele ment, andanyhow the engine is started. Some time after the start, the ice willmelt to the usual form of water with the rise of the engine temperature.

Another embodiment of the invention illustrated in FIG. 4 will now beexplained. It is equivalent to the first embodiment from which the upperend closure plate of the element (as at 6 in the embodiment shown inFIG. I) is omitted. A member l2 formed in one piece with a countersunkbody I] having a rim on the upper end of the outlet pipe 8 is provided,and the upper end of the element is bonded to the outside of the outletpipe, and is bonded altogether to the under-side of the cover Asdescribed above, even if the removal of water gathered in the casing isforgotten and the water frozen in a cold season chokes up the outletpipe, the inlet pipe remains unchoked, even with the expansion of thewater due to freezing, because the opening of the inlet pipe is abovethe lower end of the outlet pipe. Accordingly, fuel supply to the filteris possible at the time of starting, and the fuel so supplied is fed viathe by-pass opening to the engine, thus ensuring uninterrupted runningof the engine.

What is claimed is:

1, A fuel filter for engines of automobiles comprising a closed casingcomprising a body portion of a synthetic resin material and a coverportion of a synthetic resin material bonded together to form a closedhollow casing, a filter ele ment in the casing attached to the undersideof the cover por tion of the casing at its one end face, a fuel inletpipe extending through the wall of the casing vertically upwardlythrough the bottom wall of the body portion of the casing and opening inthe casing at the upper portion of the casing for introducing the fuelto be filtered to the exterior of the element, and a fuel outlet pipeextending through the wall of the casing downwardly through the coverportion of the casing and opening within the filter element at a levellower than that of the opening of the fuel inlet pipe by a distance atleast equal to the height difference between the levels of the waterintroduced in the casing as entrained on the inlet fuel stream andaccumulated in the casing to the level of the fuel outlet pipe openingbefore and after the freezing of the water, characterized by a smallby-pass opening formed through the upper portion of the wall of the fueloutlet pipe as extending in the filter element at a level higher thanthe opening of the fuel inlet pipe,

the size of the by-pass opening being so small that the by-pass openingdoes not substantially affect the amount of flow of the fuel through theopening of the outlet pipe at the end thereof.

2 The fuel filter as claimed in claim 1, one portion of the fuel outletpipe as extending in the filter element being formed of a length of apipe of a synthetic resin material adhered to the inner wall surface ofthe cover portion of the casing at its one end, another portion of thefuel outlet pipe as extending outwardly of the cover portion of thecasing being formed integrally with the cover portion of the casing andbeing in communication with the said one portion of the fuel outletpipe.

3. A fuel filter as claimed in claim 2, the filter element comprising acylindrical corrugated sheet of fiber material such as paper, an endclosure plate closing one end face of the cylindrical sheet and anotherend closure plate closing another end face of the cylindrical sheetexcept the inner portion of the end face through which the fuel outputpipe extends.

4. A fuel filter as claimed in claim 3, said another end closure platebeing formed integrally with the portion of the fuel outlet pipe asextending in the filter element.

1. A fuel filter for engines of automobiles comprising a closed casingcomprising a body portion of a synthetic resin material and a coverportion of a synthetic resin material bonded together to form a closedhollow casing, a filter element in the casing attached to the under-sideof the cover portion of the casing at its one end face, a fuel inletpipe extending through the wall of the casing vertically upwardlythrough the bottom wall of the body portion of the casing and opening inthe casing at the upper portion of the casing for introducing the fuelto be filtered to the exterior of the element, and a fuel outlet pipeextending through the wall of the casing downwardly through the coverportion of the casing and opening within the filter element at a levellower than that of the opening of the fuel inlet pipe by a distance atleast equal to the height difference between the levels of the waterintroduced in the casing as entrained on the inlet fuel stream andaccumulated in the casing to the level of the fuel outlet pipe openingbefore and after the freezing of the water, characterized by a smallby-pass opening formed through the upper portion of the wall of the fueloutlet pipe as extending in the filter element at a level higher thanthe opening of the fuel inlet pipe, the size of the by-pass openingbeing so small that the by-pass opening does not substantially affectthe amount of flow of the fuel through the opening of the outlet pipe atthe end thereof.
 2. The fuel filter as claimed in claim 1, one portionof the fuel outlet pipe as extending in the filter element being formedof a length of a pipe of a synthetic resin material adhered to the innerwall surface of the cover portion of the casing at its one end, anotherportion of the fuel outlet pipe as extending outwardly of the coverportion of the casing being formed integrally with the cover portion ofthe casing and being in communication with the said one portion of thefuel outlet pipe.
 3. A fuel filter as claimed in claim 2, the filterelement comprising a cylindrical corrugated sheet of fiber material,such as paper, an end closure plate closing one end face of thecylindrical sheet and another end closure plate closing another end faceof the cylindrical sheet except the inner portion of the end facethrough which the fuel output pipe extends.
 4. A fuel filter as claimedin claim 3, said another end closure plate being formed integrally withthe portion of the fuel outlet pipe as extending in the filter element.